1. Fields of the Invention
The present invention relates to an apparatus having a magnetic sleeve which is slidably mounted to a screwdriver bit which is not separated from the magnetic sleeve during operation.
2. Descriptions of Related Art
The conventional magnetic sleeve is disclosed in U.S. Pat. No. 7,107,882 B1 and Taiwan Patent No. 1254660, and comprises a screwdriver having a handle with a shank extending therefrom, the screwdriver having a tip at an end opposite the handle, the shank having a fastening groove formed thereon adjacent the tip, the fastening groove defining narrow diameter on the shank and a shoulder adjacent the tip; a hollow sleeve having a fastening rim slidably positioned over the fastening groove of the shank, the shoulder abutting the fastening rim when the sleeve sides outwardly of the tip so as to retain the sleeve on the shank, the fastening rim extending inwardly at one end of the sleeve; and a magnetic part affixed to an opposite end of the sleeve, the magnetic part having an outer surface suitable for magnetically connecting to a screw head, the magnetic part having interior passageway, the tip of the screwdriver slidable through the interior passageway as the fastening rim moves toward the shoulder.
However, the inner diameter of the fastening rim is smaller than the outer diameter of the front part. The magnetic sheath is made by hard plastic so that the fastening rim is forced to move over the front part, and when fastening rim reaches the groove, the inner diameter returns to its initial size, so that the magnetic sheath is difficult to be separated from the screwdriver's shank because the inner diameter of the fastening rim is smaller than the outer diameter of the screwdriver's shank.
The shortcomings of the magnetic sheath are that the magnetic sheath is integrally made of plastic, if the inner diameter of the fastening rim is not tightly engaged with the groove, the magnetic sheath may slide within the groove and cannot be well positioned. On the contrary, if the inner diameter of the fastening rim is tightly engaged with the groove, the magnetic sheath is difficult to slide. If the magnetic sheath is made of soft material, the magnetic sheath may be deformed when the user grabs it to move, and the fastening rim of the magnetic sheath may even be disengaged from the groove. Furthermore, the magnetic sheath has only one color which may not be satisfied by some users.
The present invention intends to provide an apparatus to provide a magnetic sleeve and a screwdriver bit, and eliminates the shortcomings mentioned above.